It is desirable that the dye image formed by the reaction of couplers with the oxidized form of a primary aromatic amine developing agent in a silver halide color photographic material, not fade on long term exposure to light, on short exposure to light, or upon storage for long periods of time in darkness.
Hence, in recent years ultraviolet absorbers have been added to sensitive materials in order to improve the fastness of the dye image to light. However, the light fastness of dye images formed from yellow, magenta and cyan couplers has still been found to be inadequate. There has been proposed a method in which the deterioration or elimination of the ultraviolet absorbers is prevented by dissolving the ultraviolet absorber in a high boiling point organic solvent such as phthalic acid esters and phosphoric acid esters. See JP-A-58-209735 (The term "JP-A" as used herein signifies an "unexamined published Japanese patent application"). The effect has been found to be inadequate.
A combination of benzophenone based ultraviolet absorbers and benzotriazole based ultraviolet absorbers has been suggested in JP-B-48-31255 and JP-B-48-30493, as another means of improving the light fastness of image dyes. (The term "JP-B" as used herein signifies an "examined Japanese patent publication".) However, the performance has been found to be inadequate because the ultraviolet absorbers themselves are broken down by light.
A method where a monomer latex is loaded with an ultraviolet absorber has been disclosed in British Patent 2,016,017A. But there is a disadvantage here in that a large quantity of polymer latex must be used relative to the amount of ultraviolet absorber in order to provide an adequate improvement in light fastness. Moreover, there are additional problems in that impurities such as emulsifying agents and unreacted monomer used during the preparation of the monomer latex and the polymerization inhibitor, have an degrading effect on the dyes.
A method in which an ultraviolet absorber monomer latex is used has also been disclosed in JP-A-58-185677. But this technique only prevents the occurrence of yellow staining which is produced on the white base upon irradiation with light.
A method for improving the light fastness of both the ultraviolet absorbers themselves and the dye image by emulsification and dispersion of the ultraviolet absorber together with certain hydrophobic polymers is disclosed in JP-A-63-264748. However, satisfactory results have not been obtained. Other problems have been observed as well. Large amounts of monomer must be added relative to the amount of ultraviolet absorber in order to satisfactorily improve the light fastness of the ultraviolet absorber. As a result, a large dissolution time is required. Moreover, the mixed solution will have has a high viscosity making emulsification and dispersion difficult; coarse particles are easily produced causing coating failures.